The first-ever credit downgrade of the U.S. left Wall Street and Washington struggling to come to grips with a new world order. With the U.S. stripped by Standard & Poor’s of its triple-A credit rating, big banks brought in people to staff trading desks over the weekend, and Obama administration officials put a full-court press on skittish investors. Treasury Secretary Timothy Geithner—who agreed to stay through the 2012 election—told NBC News that “S&P has shown really terrible judgment.”